Soybean straw (SS) was modified with citric acid (CA) to prepare a new adsorbent (CA-SS) to study the heavy metal adsorption efficiency of SS. The morphological and chemical characteristics of the adsorbent were evaluated through SEM and FTIR analysis. The copper ion (Cu2+) adsorption capability of SS and CA-SS were compared, the effects of initial Cu2+ concentration, contact time and competitive ions were studied, and the adsorption dynamics and thermodynamicswereanalyzed. The results show that the porous structure of SS was preserved after modification, but the carboxyl groups were introduced onto SS. The pseudo-second-order model and Langmuir equation were suited to describe the dynamics and thermodynamics data. The maximum adsorption capacity increased from 10.44 mg/g to 19.14 mg/g according to the Langmuir model. The reason for the increase was that the introduced carboxyl groups increase the net negative charge on the SS, thereby increasing its binding potential for metal ions. Furthermore, Cu2+ exhibits better competiveness than Ni2+; the competitive adsorption in the binary system is related to the chemical properties of each element. CA-SS may be used as a lowcost alternative adsorbent for the decontamination of metal-containing effluent.
ZHANG Ruzhuang
,
ZHOU Yanbo
,
GU Xiaochen
,
LU Jun
. Adsorption Behavior of Citric Acid Modified Soybean Straw for Cu2+[J]. Science & Technology Review, 2014
, 32(14)
: 15
-18
.
DOI: 10.3981/j.issn.1000-7857.2014.14.001
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